Summary: The text discusses the fundamental position of relativity physics and the implications it has on our understanding of the universe and reality. It highlights the complex nature of concepts in physics, such as the ether, electric and magnetic forces, and light, which are all essential in our perception of the world but remain undefinable in terms familiar to the mind. The text delves into the limitations of logical categories when applied to elements of experience and the inherent contradictions that arise when trying to explain familiar concepts in unfamiliar terms. It also touches upon how relativity physics and quantum phenomena have increased rather than lessened the difficulties faced by physicists in understanding the core of being. The discussion emphasizes the mystery and unintelligibility that underlie our comprehension of the universe, suggesting that even with scientific progress, there will always be aspects that elude complete understanding.